Maltobionic acid

Lewis201 postulated maltosone as the first product in the oxidation of maltose by Fehling solution, but no osone was detected when maltose was treated with Fenton s reagent.23 Oxidation of maltosone with bromine water gave 2-oxo-maltobionic acid, isolated as its brucine salt.191... 

The application of this method of oxidation to the disaccharides without accompanying hydrolysis was successful and proved to be a valuable structural tool in showing the nature of the linkage between the two sugar units. Lactose was converted to lactobionic acid (33% yield) by Fischer and Meyer the sugar was treated with an equal weight of bromine at 20° for two days. Several salts were prepared, notably the insoluble basic lead salt, but the free acid would not crystallize. Ruff and Ollen-dorf reported a 38% jdeld, isolated as the calcium salt. Fischer and Meyer also reported the preparation of maltobionic acid, as the basic lead or calcium salt both were non-crystalline. 

Another method of preparing keto aldonic acids, those of the 2-keto type, is by oxidation of the corresponding osone. Neuberg and Kitasato obtained 18 g. of calcium 2-keto-D-gluconate from 20 g. of the osone by the action of bromine at 20 . Similarly, 2-keto-n-galactonic and 2-keto-maltobionic acids were prepared by Kitasato. The substances were characterized generally as the brucine salts because of the amorphous nature of the calcium salts. 

Glattfeld and Hanke applied this procedure to the oxidation of maltose hydrate. An aqueous solution of the sugar was shaken with lead carbonate and bromine since lead bromide separated from the reaction mixture, only aeration was necessary to remove the excess bromine, and treatment with silver oxide and hydrogen sulfide removed the last bromide, silver and lead ions. The maltobionic acid was isolated as the calcium salt. Here the neutralization of the hydrobromic acid was beneficial in preventing any hydrolysis of the aldobionic acid. 

In 1931, Isbell and Frush reported the electrolytic oxidation of aldoses in the presence of calcium carbonate and a small amount of bromide, which served as a catalyst. The main solutes in the reaction mixture are the aldose and the calcium salt of the aldonic acid. The latter is easily crystallized from solution. The salts of D-gluconic, D-xylonic, lactobionic and maltobionic acids were prepared. A description of the process was published in 1932 and a patent was issued in 1934. German and French patents were issued in 1931 to the Rohm and Haas Co. ... 

Oxidation by bromine water converts (+)-maltose into ihe monocarboxylic acid D-maltobionic acid. Treatment of this acid with methyl sulfate and sodium hydroxide yields (octa-O-methyl-D-maltobionic acid. Upon hydrolysis in acidic solution, the methylated acid yields two products, 2,3,5,6-tetra-O-methyl-o-gluconic acid and 2,3,4,6-tetra-O-methyl-D-glucose. 

Fig. 2.—Curves of Rate against Temperature. (A, maltose B, maltitol C, maltose phenylosotriazole D, maltose cyanohydrin E, maltobionic acid F, maltose 1-phenyl-flavazole.)...

PevJla-acetyl C HanO from Etj,0-MeOH in CHag. Sol. CHCI3, EtOH. H3O. Reduces Fehlii s in hot. See previous reference. Maltobionic Acid pOOH... 

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